Disk array controller, its disk array control unit, and increase method of the unit

Abstract

A disk array controller is made up of multiple disk array control units for implementing the data read/write operation and each having channel IF units, disk IF units, cache memory units and shared memory units. The disk array controller further includes interconnections for interconnecting the shared memory units and interconnecting the cache memory units across the border of disk array control units. Thereby alleviating the deterioration of performance due to the data transfer between the disk array control units, when the multiple disk array control units are to be operated as a single disk array controller.

What is claimed is:  
     
       1. A disk array controller comprising: 
       a plurality of disk array control units, each having one or more channel interface units for interfacing with a host computer;  
       one or more disk interface units for interfacing with disk drives;  
       a cache memory unit for temporarily storing data which is written to or read out of said disk drives; and  
       a shared memory unit for storing control information of data transfer between each of said channel interface units and each of said disk interface units and said cache memory unit and control information for said disk drives,  
       wherein each of said disk array control units implementing the data read/write operation in response to a data read/write request from said host computer by operating on each of said channel interface units to transfer data between an interface with said host computer and said cache memory unit and operating on each of said disk interface units to transfer data between said disk drives and said cache memory unit,  
       wherein said channel interface units and disk interface units and said cache memory units in said disk array control units having their connection nodes interconnected through a first interconnection across the border of disk array control units, and  
       wherein said channel interface units and disk interface units and said shared memory units in said disk array control units having their connection nodes interconnected through a second interconnection across the border of disk array control units.  
     
     
       2. A disk array controller according to  claim 1 , wherein said channel interface units and disk interface units and said cache memory units in said multiple disk array control units are connected through said first interconnection, and said channel interface units and disk interface units and said shared memory units are connected through said second interconnection. 
     
     
       3. A disk array controller according to  claim 1 , wherein said channel interface units and disk interface units and said cache memory units in said multiple disk array control units are connected by said first interconnection, and said channel interface units and disk interface units and said shared memory units are connected directly for the portion within each disk array control unit. 
     
     
       4. A disk array controller according to  claim 1 , wherein said channel interface units and disk interface units and said cache memory units in said multiple disk array control units are connected for the portion within each disk array control unit through a third interconnection in each disk array control unit, and said channel interface units and disk interface units and said shared memory units are connected directly for the portion within each disk array control unit. 
     
     
       5. A disk array control unit comprising: 
       one or more channel interface units for interfacing with a host computer;  
       one or more disk interface units for interfacing with disk drives;  
       a cache memory unit for temporarily storing data which is written to or read out of said disk drives; and  
       a shared memory unit for storing control information of data transfer between each of said channel interface units and each of said disk interface units and said cache memory unit and control information for said disk drives,  
       wherein said disk array control unit implementing the data read/write operation in response to a data read/write request from said host computer by operating on each of said channel interface units to transfer data between an interface with said host computer and said cache memory unit and operating on each of said disk interface units to transfer data between said disk drives and said cache memory unit, and  
       wherein said disk array control unit having, on the connection node of each of said channel interface units and each of said disk interface units and said cache memory unit, a first connection path for the connection with another disk array control unit, and having, on the connection node of each of said channel interface units and each of said disk interface units and said shared memory unit, a second connection path for the connection with said another disk array control unit.  
     
     
       6. A disk array control unit according to  claim 5 , wherein said disk array control unit is built on a rack, and said first and second connection paths have connectors. 
     
     
       7. A disk array controller comprising: 
       a plurality of disk array control units, each having one or more channel interface units for interfacing with a host computer;  
       one or more disk interface units for interfacing with disk drives;  
       a cache memory unit for temporarily storing data which is written to or read out of said disk drives; and  
       a shared memory unit for storing control information of data transfer between said channel interface unit and disk interface unit and said cache memory unit and control information for said disk drives,  
       wherein each of said disk array control units implementing the data read/write operation in response to a data read/write request from said host computer by operating on each of said channel interface units to transfer data between an interface with said host computer and said cache memory unit and operating on each of said disk interface units to transfer data between said disk drives and said cache memory unit,  
       wherein each of said disk array control units having, on the connection nodes of each of said channel interface units and each of said disk interface units and said cache memory unit, a first connection path for the connection with another disk array control unit, and having, on the connection nodes of each of said channel interface units and each of said disk interface units and said shared memory unit, a second connection path for the connection with said another disk array control unit; and  
       a switch box which is connected with said first and second connection paths of each of said disk array control units, thereby integrating each of said disk array control units functionally into a single disk array controller.  
     
     
       8. A method of increasing the number of disk array control units in a disk array controller which comprises: 
       a plurality of disk array control units each having one or more channel interface units for interfacing with a host computer;  
       one or more disk interface units for interfacing with disk drives;  
       a cache memory unit for temporarily storing data which is written to or read out of said disk drives; and  
       a shared memory unit for storing control information of data transfer between each of said channel interface units and each of said disk interface units and said cache memory unit and control information for said disk drives, and implementing the data read/write operation in response to a data read/write request from said host computer by operating on each of said channel interface units to transfer data between said interface with said host computer and said cache memory unit and operating on said disk interface units to transfer data between said disk drives and said cache memory unit,  
       wherein each of said disk array control units having, on the connection nodes of each of said channel interface units and each of said disk interface units and said cache memory unit, a first connection path for the connection with another disk array control unit, and having, on the connection nodes of each of said channel interface units and each of said disk interface units and said shared memory unit, a second connection path for the connection with said another disk array control unit; and  
       a switch box which is connected with said first and second connection paths of each of said disk array control units, thereby integrating said disk array control units functionally into a single disk array controller,  
       wherein said first and second connection paths and said switch box having connectors, and  
       wherein said switch box having its connectors connected by cables to connectors of the first and second connection paths of a disk array control unit to be added to said disk array controller,  
       said method comprising the steps of:  
       providing connectors to said first and second connection paths and said switch box,  
       connecting said connectors of the first and second connection paths of a disk array control unit to said connectors of said switch box.  
     
     
       9. A method of increasing disk array control units according to  claim 8 , wherein said switch box has an information table for storing information indicative of the correspondence between the destination address of data which is transferred through said switch box and information which indicates a disk array control unit to be connected, said information table being rendered the addition of correspondence information for a disk array control unit to be added to said disk array controller. 
     
     
       10. A method of increasing disk array control units according to  claim 8 , wherein said disk array control units are built on individual racks and said switch box is built together with a disk array control unit on one of said racks, said switch box having the connection of a plurality of cables which are connected to racks of other disk array control units. 
     
     
       11. A disk array controller being built on a single rack comprising: 
       a plurality of disk array control units, each having one or more channel interface units for interfacing with a host computer;  
       one or more disk interface units for interfacing with disk drives;  
       a cache memory unit for temporarily storing data which is written to or read out of said disk drives;  
       a shared memory unit for storing control information of data transfer between each of said channel interface units and each of said disk interface units and said cache memory unit and control information for said disk drives,  
       wherein each of said disk array control units implementing the data read/write operation in response to a data read/write request from said host computer by operating on each of said channel interface units to transfer data between an interface with said host computer and said cache memory unit and operating on each of said disk interface units to transfer data between said disk drives and said cache memory unit,  
       wherein each of said disk array control units having, on the connection nodes of each of said channel interface units and each of said disk interface units and said cache memory unit, a first connection path for the connection with another disk array control unit, and having, on the connection nodes of each of said channel interface units and each of said disk interface units and said shared memory unit, a second connection path for the connection with said another disk array control unit; and  
       a switch box which is connected with said first and second connection paths of each of said disk array control units, thereby integrating said disk array control units functionally into a single disk array controller.